Excavator tooth assembly



July 18, 1961 G, w, MORK 2,992,498

EXCAVATOR TOOTH ASSEMBLY Filed March 10, 1959 I 1,9 202,6Z1b2l 210.2528 9 4 ,':==.w 9 11 e n l5 I6 Ma. l

INVENTQR Genus: W. Monk ATTORNEY United States Patent EXCAVATOR TOOTH ASSEMBLY George W. Mark, South Milwaukee, Wis., assignor to Bucyrus-Erie Company, South Milwaukee, Wis., a corporalion of Delaware Filed Mar. 10, 1959, Ser. No. 798,549 6 Claims. (Cl. 37-142) This invention relates to a digger tooth assembly such as those used on ripping implements, scarifying tools and buckets of excavators or the like.

A general object of this invention is to provide an excavator tooth assembly which has a base and a detachable tip with a simple latch means to maintain the com ponent parts of the tooth in operative position. Such tooth assemblies have in the past been excavator teeth commonly provided with aligned holes in the tip and tooth base and some sort of resilient retaining means fitted in said holes to operably lock the two portions together. In some designs, the aligned holes are in both a horizontal and a vertical plane; in other designs the aligned holes are in one plane only.

' A disadvantage of such designs from an economic point of view is the fact that the tooth components must be machined so that theholes which receive the latching means will be substantially aligned when the component parts are fitted together.

\ Most excavator teeth are subjected to extremely severe service; therefore, metal used in making the teeth must have satisfactory wear resistance and strength. Cast, rather than forged, steel is usually used for the components of such teeth. Since it is diflicult to maintain exact dimensions of cast steel components, it is desirable to eliminate the need for precise dimensional control and accurate machining of the component parts of the tooth assembly.

Therefore, it is an object of the invention to provide an excavator tooth assembly which substantially eliminates the need for exact dimensional tolerances.

It is also an object of the invention to provide a latching means that will retain a tooth tip in operating position in an excavator tooth assembly and will urge the tip into contact with the cooperating portion of the tooth base.

Another object of the invention is to provide an excavator tooth assembly with a latching mechanism which will maintain itself in a locked condition.

A further object of the invention is to provide an excavator tooth assembly with a latching means which permits ready removal of a worn tip and attachment of a new tip without the use of special tools.

In addition to the principal objects, above stated, a number of novel and useful details have been worked out, which will be readily evident as the description progresses.

The invention consists in the novel parts and in the combination and arrangements thereof, which are defined in the appended claims, and of which different embodiments are exemplified in the accompanying drawings which are hereinafter particularly described and explained.

Throughout the description, the same reference number is applied to the same member or to similar members.

FIGURE 1 is a top plan view of a digger tooth assembly embodying the invention.

FIGURE 2 is a vertical cross-sectional view taken on line 22 of FIGURE 1.

FIGURE 3 is similar to FIGURE 2 except that the latching means is shown in an unlocked position.

FIGURE 4 is a sectional view of the tooth taken on line 4-4 of FIGURE 3.

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FIGURE 5 is a sectional view of the tooth taken on line 55 of FIGURE 3.

As shown in FIGURES 1 and 2 the excavator tooth assembly comprises a tooth base 10, a tooth tip 11 and latching means generally indicated at 12 which retains the tip in an operating position with respect to the tooth base. The tooth base is shown as being mounted by any suitable means on a portion of a bucket edge 13 which could also be any other type of supporting means when the tooth assembly is used in conjunction with a ripping implement or .scarifier.

The tooth base 10 is provided with an integral forwardly projecting nose portion 14a, which is wedgeshaped in cross-section as viewed in FIGURE 2. The tooth base is also provided with a rear shank portion 14b at the end opposite the nose portion 14a. Preferably, the projecting nose has upper and lower wedge surfaces and substantially parallel side surfaces. Adapted for removable mounting upon the projecting nose 14a of the tooth base is a tooth tip 11 having a forwardly projecting spike portion 15 and a rearwardly opening wedge-shaped socket 16. The side walls 17 of the socket are substantially parallel and the upper and lower walls are provided with a matching taper that is complementary with and corresponds to the taper provided on the projecting nose 14a of the tooth base. The cooperating tapered socket and the tapered nose portion transmit all thrust forces to the tooth tip.

On the upper surface of both the tooth base 10 and the tip 11 a longitudinal recess or channel 118, 19, is provided to receive a latch means 12 which retains the tip on the base in operating position. The channel 18 in the tip and 19 in the base accommodates the entire latch means so that the entire tooth assembly has a relatively smooth upper surface when the latch means is in a locked position as shown in FIGURE 2.

The channel 18, 19 is provided on the upper surface of the tooth base and tip to render the latch means easily accessible.

The latch means 12 comprises an elongated retaining member 20 and a relatively short toggle link 21 which serves as a locking member. The retaining member 20 is preferably in the form of a spring steel clip provided with a pair of sharply inwardly curved, or hooked, anchor ends 22 and 23 and an elongated, gently inwardly curved intermediate portion 24. The toggle link 21 is provided with at least one pair of opposed, rounded ends 21a and 21b adapted to engage either of the anchor ends 2223 of the retaining member 20. The toggle link and the retaining member are dimensioned in such a manner that when placed in an over-center, locked position as shown in FIGURE 2, the retaining member 20 is elongated and tends to assume a straight line position; the internal stresses in member 20 thereby exert a positive force acting to maintain the tip 11 on the tooth base it? in an operative position.

Both the tip 11 and the tooth base 10 are provided with a locking anchorage adapted to cooperate with the latch means 12. The upper wall of the socket 16 in the tip is provided with an anchorage 25 adapted to engage either anchor end of the retaining member 20. The rear shank portion 14b of the tooth base is provided with an anchorage 26 in the form of a curved projection to provide a reaction surface for the toggle link 21. The bearing surface of the anchorage is preferably rounded in a manner complementary to the rounded ends of the togglelink to facilitate angular rotation of the link about the bearing surface of the anchorage which serves as the pivot axis of the link.

The sequence of assembling the excavator tooth is first to insert the nose portion 14a of the tooth base 10 into the socket 16 of the tooth tip 11. The spring clip 20 is then positioned so that one anchor end 22 engages the anchorage 25 of the tooth tip and the other anchor end 23 engages an end 21a of the togglelink 21 The opposite end 21b of the link is then engaged with the anchorage 26 provided in the tooth base 10. The latching means 12 is then in a position shown in FIGURE 3; by exerting a downward force on the spring clip 20 at a point near the anchor end that engages the toggle link 21, the clip will be deflected outwardly to a maximum as the end 23 of clip 20 is lowered so that the center of contact of the bearing surface on the anchorage 26 which serves as a pivot axis for toggle link 21 is aligned with the centers of contact of the bearing surfaces of the anchor ends 22 and 23. Further downward movement of the retaining clip 24) causes the clip to assume an over-center position relative to said pivot axis as shown in FIGURE 2. The line of force F exerted by the spring clip 2t) is now below the pivot axis of the toggle link 21 and will retain the spring clip in an overcenter position in relation to the pivot axis; A stop 27 is provided on the rear shank portion 14b to limit movement of the toggle link 21 and maintain the locked position of the latch mechanism. The stressed condition of the clip 20 will thus provide a constant force on the tip 11 to maintain the tip on the tooth base in an opera tive position and also maintain the latch means 12 in a locked position. If the tooth assembly is to be subjected to mechanical shocks in a vertical plane, it may be desired to provide a simple keeper member such as is illustrated at 28 to prevent inadvertent unlocking of the latch means 12. The keeper may be retained on the tooth base by means of a capscrew 29 threaded into a tapped hole 30 provided in the base.

Removal of the tip is performed by first removing the keeper 28, if one has been provided, and then unlocking the latch means 12 to permit the tip 11 to be removed and a new tip attached as soon as replacement is required. In the event that a slight dimensional difference occurs in the new tip resulting in an increase in the efiective distance between the surfaces of the anchorages 25 and 26, so that the length of toggle link 21 will not permit latch means 12 to be moved to an over-center, locked position, the link 21 may be merely rotated 90 degrees, as viewed in FIGURE 1, so that its shorter dimension may serve as the eifective toggle length in the latch means. The toggle link is preferably dimensioned of a width slightly less than its length and of a length which does not exceed the width of the channel 19 in the tooth base.

Thus, it is seen that as dimensional variations do occur in the component of the tooth itself, the invention has provided a latching means which readily adapts itself to variations in the distance between the anchorages and the tooth tip and the tooth base.

Having now described and illustrated one form of the invention, it is to be understood that this invention is not to be limited to the specific form or arrangement of parts herein described and shown.

What is claimed is:

1. In an excavator tooth having a tooth base portion, a tip receivable on said tooth base, and a separate anchorage on both the tip and the base, a latch mechanism between said anchorages to retain the tip on the base in an operative position, said latch mechanism comprising; a link having one end thereof pivotally engaging one of said anchorages to serve as a pivot axis for said link; an elongated spring clip having a pair of anchor ends; one of said anchor ends pivotally engaging the opposite end of said link; the other of said anchor ends pivotally engaging the other of said anchorages; said latch mechanism having an unlocked first position in which a line drawn between the anchor ends of said clip passes above said pivot axis of said link, and said latch mechanism having a locked second position in which a line drawn between the anchor ends of said clip passes below said pivot axis.

2. An excavator tooth comprising a tooth base having a rear shank portion and an integral forwardly-projecting nose portion; a separate tooth tip provided with a rearwardly opening socket and positioned on said nose por tion; an anchorage on said tip; an anchorage on said rear shank portion; a toggle stop on said rear shank portion; and latch means connected between said anchorages to' retain said tip on said base; said latch means including an elongated inwardly curved spring clip provided with a pair of anchor ends; and a toggle link substantially shorter than said spring clip; wherein one of the anchor ends of said spring clip is connected to the anchorage on said tip; the other anchor end of said clip is engaged with one end of said toggle link; the opposite end of said toggle link is engaged with the anchorage on said rear shank portion which serves as a pivot axis for said link; said clip and said toggle link having an unlocked first position in which said toggle link is spaced from said stop and a line drawn between the anchor ends of said clip passes above said pivot axis; said spring clip and said toggle link having a locked second position in which said link is in contact with said stop and a line drawn between the anchor ends of said clip passes below said pivot axis.

3. A construction according to claim 2 in which the upper side of both the tooth base and the tooth tip is provided with a longitudinal channel intermediate the ends of the tooth assembly to receive the intermediate portion of said spring clip.

4. A construction according to claim 3 in which said longitudinal channel is of a depth at least equal to the thickness of said spring clip.

5. A construction according to claim 3, further characterized by the fact that the width of said channel is at least equal to the length of said toggle link.

6. A construction according to claim 5, in which the togglf link has a length only slightly greater than its widt References Cited in the file of this patent UNITED STATES PATENTS 1,827,319 Komenak Oct. 13, 1931 2,325,991 White Aug. 3, 1943 2,867,863 Webb et al. Jan. 13, 959 

